Today I was making some measurements with my MFJ-259B. From the manual,
I read:

"The MFJ-259B measures reactance, and converts reactance to
capacitance. The MFJ-259B
can not determine if the reactance is actually inductive or capacitive.
You can usually determine
the type of reactance by adjusting frequency. If frequency is increased
and reactance (X on the
display or Impedance on the meter) decreases, the load is capacitive at
the measurement
frequency. If frequency is reduced and reactance decreases, the load is
inductive at the
measurement frequency."

Then I looked over the measurements that I plotted out. If I look at
the graph of the reactance, the amplitude of the reactance will
increase and then begin to decrease as frequency increases. If I try to
follow the tip given in the MFJ manual, the reactance can appear as
both capactive and reactive before it ever crosses zero. For instance
if I follow the graph it rises and then starts to fall - according to
the manual this would mean the upside is inductive and the downside is
capacitive. But what I don't understand is how that is possible - it
seems to me it would have to cross the integer value zero (0) to change
from capacitive reactance to inductive reactance?

What concept am I screwing up here?

-Scott, WU2X

Here are the values I measured:


Freq R X SWR
--------------------------------------
144 44 2 1.1
144.25 46 4 1.1
144.5 55 7 1.1
144.75 60 7 1.2
145 68 0 1.3
145.25 78 0 1.4
145.5 79 0 1.4
145.75 73 11 1.5
146 63 21 1.5
146.25 53 23 1.5
146.5 46 21 1.5
146.75 40 18 1.5
147 37 10 1.5
147.25 35 8 1.4
147.5 37 6 1.3
147.75 41 10 1.3
148 48 15 1.3
148.25 59 19 1.4
148.5 75 16 1.6
148.75 90 0 1.7
149 96 6 1.9